Oceanibulbus indolifex gen. nov., sp. nov., a North Sea alphaproteobacterium that produces bioactive metabolites

1 GBF – Gesellschaft für Biotechnologische Forschung, D-38124 Braunschweig, Germany 2 Technical University of Braunschweig, D-38106 Braunschweig, Germany 3 University of Göttingen, D-37077 Göttingen, Germany 4 DSMZ – Deutsche Sammlung von Mikroorganismen und Zellkulturen, D-38124 Braunschweig, Germany Correspondence Irene Wagner-Döbler iwd{at}gbf.de A water sample from the North Sea was used to isolate the abundant heterotrophic bacteria that are able to grow on complex marine media. Isolation was by serial dilution and spread plating. Phylogenetic analysis of nearly complete 16S rRNA gene sequences revealed that one of the strains, HEL-45 T , had 97·4 % sequence similarity to Sulfitobacter mediterraneus and 96·5 % sequence similarity to Staleya guttiformis . Strain HEL-45 T is a Gram-negative, non-motile rod and obligate aerobe and requires sodium and 1–7 % sea salts for growth. It contains storage granules and does not produce bacteriochlorophyll. Optimal growth temperatures are 25–30 °C. The DNA base composition (G+C content) is 60·1 mol%. Strain HEL-45 T has Q10 as the dominant respiratory quinone. The major polar lipids are phosphatidyl glycerol, diphosphatidyl glycerol, phosphatidyl choline, phosphatidyl ethanolamine and an aminolipid. The fatty acids comprise 18 : 1 7 c , 18 : 0, 16 : 1 7 c , 16 : 0, 3-OH 10 : 0, 3-OH 12 : 1 (or 3-oxo 12 : 0) and traces of an 18 : 2 fatty acid. Among the hydroxylated fatty acids only 3-OH 12 : 1 (or 3-oxo 12 : 0) appears to be amide linked, whereas 3-OH 10 : 0 appears to be ester linked. The minor fatty acid components (between 1 and 7 %) allow three subgroups to be distinguished in the Sulfitobacter / Staleya clade, placing HEL-45 T into a separate lineage characterized by the presence of 3-OH 12 : 1 (or 3-oxo 12 : 0) and both ester- and amide-linked 16 : 1 7 c phospholipids. HEL-45 T produces indole and derivatives thereof, several cyclic dipeptides and thryptanthrin. Phylogenetic analysis of 16S rRNA gene sequences and chemotaxonomic data support the description of a new genus and species, to include Oceanibulbus indolifex gen. nov., sp. nov., with the type strain HEL-45 T (=DSM 14862 T =NCIMB 13983 T ). Abbreviations: DMSP, dimethylsulfiopropionate Published online ahead of print on 5 March 2004 as DOI 10.1099/ijs.0.02850-0. The EMBL/GenBank/DDBJ accession number for the 16S rRNA gene sequence of HEL-45 T is AJ550939 . Present address: Bayer AG, D-51368 Leverkusen, Germany.